<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">

    <title>(1)文本/行内元素/行内块级元素</title>
    <style>
        #parent {
            text-align: center;
            background: #ff2133;
        }

    </style>
</head>
<body>

<div id="parent">
           <span>
               儿子
           </span>
</div>
</body>
</html>